xfs: cleanup up xfs_log_force calling conventions

Remove the XFS_LOG_FORCE argument which was always set, and the
XFS_LOG_URGE define, which was never used.

Split xfs_log_force into a two helpers - xfs_log_force which forces
the whole log, and xfs_log_force_lsn which forces up to the
specified LSN.  The underlying implementations already were entirely
separate, as were the users.

Also re-indent the new _xfs_log_force/_xfs_log_force which
previously had a weird coding style.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
diff --git a/fs/xfs/xfs_vnodeops.c b/fs/xfs/xfs_vnodeops.c
index 4da96cd..fd108b7 100644
--- a/fs/xfs/xfs_vnodeops.c
+++ b/fs/xfs/xfs_vnodeops.c
@@ -631,9 +631,8 @@
 		xfs_iunlock(ip, XFS_ILOCK_SHARED);
 
 		if (xfs_ipincount(ip)) {
-			error = _xfs_log_force(ip->i_mount, (xfs_lsn_t)0,
-				      XFS_LOG_FORCE | XFS_LOG_SYNC,
-				      &log_flushed);
+			error = _xfs_log_force(ip->i_mount, XFS_LOG_SYNC,
+					       &log_flushed);
 		} else {
 			/*
 			 * If the inode is not pinned and nothing has changed